Pen



FIG. 1 is a left side elevation view of a pen showing my new design;

FIG. 2 is a front elevation view of the pen of FIG. 1;

FIG. 3 is a right side elevation view of the pen of FIG. 1;

FIG. 4 is a rear elevation view of the pen of FIG. 1;

FIG. 5 is a bottom plan view of the pen of FIG. 1;

FIG. 6 is a top plan view of the pen of FIG. 1; and,

FIG. 7 is a perspective view of the pen of FIG. 1, showing environment.

The broken lines in the figures show portions of the pen which form no part of the claimed design. 

CLAIM The ornamental design for a pen, as shown and described. 